Effect of trace carbon on the dynamic compressive properties in the as-cast Ti13V11Cr3Al alloy

An as-cast Ti13V11Cr3Al titanium alloy was fabricated via vacuum induction skull melting. The microstructure and mechanical properties of this alloy were characterized via transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy (EDX) and compression experiments, respectively. The results revealed that trace impurity carbon (0.014 wt%) led to the formation of in-situ needle-like TiC precipitates during solidification. To reveal the underlying mechanism governing this formation, the (Ti13V11Cr3Al)-C pseudo-phase equilibrium diagram was constructed using JMatPro software. The results suggested that the precipitation of TiC will occur if the carbon content is > 0.003 wt%. Under high strain rate conditions, small volume fractions of these precipitates can lead to improvements in the ductility, and retention of the strength (1350 MPa). The as-cast alloy exhibited excellent dynamic plasticity, as evidenced by a critical fracture strain of >35% at a strain rate of 4158/s. In addition, microstructural observation of adiabatic shear bands revealed that debonding of the TiC precipitates from the matrix required considerable energy dissipation. Moreover, a crack propagated along the boundary of the precipitates, thereby leading to significant improvement in the dynamic plasticity from the other respect.